试题与答案

运动物体接近光速会出现令人费解的现象。对随光一起旅行的任何物体和人员来说,时间慢

题型:单项选择题

题目:

  运动物体接近光速会出现令人费解的现象。对随光一起旅行的任何物体和人员来说,时间慢了下来。这是爱因斯坦的狭义相对论的部分内容,利用原子钟进行的实验证明了这一点。并非只有时钟减慢,化学反应和生物过程也减慢了。这一现象叫时间膨胀。

  运动速度和时间变化不是简单的线性关系。光速降到一半或四分一时,时间变化率并没有分别降到一半或四分之一。只有速度十分接近光速时,时间膨胀才明显。时间膨胀成为现实,令人惊叹不已。速度十分接近光速时,空间旅行者衰老的速度是没有进行旅行的人的千分之一或万分之一。在地球上已过去了10万年,而我们的空间冒险者也许只长了10岁。地球上已经历数代沧桑,文明已经历多次兴衰,冰期出现又消失多次。这位冒险者在空间仅度过10年。人类在时间膨胀中生活,生命好像暂时停止了,实际上能够到遥远的恒星和其他星系中旅行,最主要的障碍是我们无法达到光速。

  时间膨胀不仅为探索人类能力所不能及的宇宙提供了方法,它也是一种时间旅行(一种科学幻想活动,指人离开现在而置身于未来或过去――译注)。如果空间旅行者能活万岁,那么他们不就在未来旅行吗,体验未来吗毕竟,他们在“过去”的9920年前就去世了(假定人的寿命为80岁)。我们假定,时间膨胀的现象不是时间旅行――既不是未来时间的一部分,也不是过去时间的一部分。我们都知道即使用光速旅行也需要时间,旅行做不到即刻到达。例如,光从月球到地球需要1秒多钟。阳光到达地球需要约8分钟。半人马座比邻星的光到达地球需要4.2年,M104星系的光到达地球需要4000万年。我们抬头看到的月亮是1秒钟之前的月亮,太阳光是在8分钟前出现的,半人马座比邻星闪烁的光是4.2年前的,用功能很强的望远镜看到的M104星系发出的光是4000万年前的。我们所见到的一切都是过去的。我们生活在过去。如果太阳突然爆炸并消失,我们仍能看到它在空中又持续闪耀8分钟。在这8分钟内,我们仍受到其重力的影响。

下列对时间描述不准确的一项是()。

A.光从月球到地球需要1秒多钟

B.阳光到达地球需要约8分钟

C.半人马座比邻星的光到达地球需要4.2年

D.M104星系的光到达地球需要4000多年

答案:

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下面是错误答案,用来干扰机器的。

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题型:单项选择题

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